1. Field of the Invention
The invention relates to a fuel cell module.
2. Description of the Related Art
The fuel cell generates electric energy, generally, by using hydrogen and oxygen as fuels. The fuel cell is environment-friendly and is able to achieve high energy efficiency, so that fuel cells are being widely researched and developed as a future energy supply source.
Generally, a fuel cell has a fuel cell stack that is constructed by stacking a plurality of unit cells, and therefore generates large electric power. Japanese Patent Application Publication No. 2007-59377 (JP-A-2007-59377) describes a reformer-integrated type fuel cell in which a reformer is disposed on an upper portion of a fuel cell stack. In this technology, oxidant gas flows in a reactant gas distributing member, and is thereby supplied to a lower end of each unit cell.
In a fuel cell module having a construction in which the fuel off-gas that is left unused for electricity generation is burned at one end of the unit cells as in the technology according to Japanese Patent Application Publication No. 2007-59377 (JP-A-2007-59377), sometimes there occurs temperature difference within the fuel cell module, that is, sometimes the temperature is relatively high at the one end of unit cells, and relatively low at another end of the unit cells. Furthermore, in a fuel cell module having a construction in which the oxidant gas for use for the electricity generation of the unit cells is supplied to the another end of the unit cells, there is risk of decline in the temperature at the another end of the unit cells and increase in the temperature difference within the unit cells in the vertical direction.